Untersuchungen zum Phasendiagramm und der Kationendiffusion im System La 1-x Sr x Ga 1-y Mg y O 3-(x+y)/2 (LSGM)

This theses can be subdivided into three parts: 1. Solid phase equilibria in the quasi quaternary system La2O3-Ga2O3-SrO-MgO near the solubility lobe of the (La,Sr)(Ga,Mg)O3- perovskite phase were determined by XRD, SEM/EDX and EPMA of annealed and quenched samples. Polycrystalline, dense samples of the oxygen ion conductor LSGM (lanthanum gallate, doped with strontium on A- and magnesium on B-sites (La1-XSrXGa1-YMgYO3- (X+Y)/2)), were then prepared using the Pechini method [1]. Characterization by X-ray diffraction showed that all resulting samples, which are preannealed at 1400°C in air are single phase [2]. 2. Results for the cation self and impurity diffusion coefficients of different cations were obtained by SIMS (Secondary Ion Mass Spectrometry). Two different mechanisms (grain boundary and bulk diffusion) have been found and ratios of grain boundary to bulk diffusion coefficients have been calculated. The temperature dependence of diffusion in differently doped LSGM was investigated for temperatures between 900°C and 1400°C. 3. Based on these results a coupled transport mechanism for the cations in LSGM was suggested. The results were compared with results from theoretical calculations [3]. [1] M. P. Pechini, U.S. Pat. Nr. 3 330 697, 11. July 1967 [2] A. Matraszek, D. Kobertz, L. Singheiser, K. Hilpert, W. Kuncewicz-Kupczyk, M. Miller, O. Schulz und M. Martin, Materialwissenschaft und Werkstofftechnik, in print (2002) [3] R. A. De Souza und J. Maier, to be published

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2003

Author dc:creator

• Schulz, Olaf

Contributors dc:contributor

• Martin, Manfred

• info:eu-repo/classification/ddc/540
• Chemie
• Kationendiffusion
• LSGM
• SOFC

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-120735%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:58909